The objective of this proposal is to study the respiratory effects of exposure to cotton dust in a population of cotton textile mill workers surveyed in Shanghai. The population selected for survey processes hand picked cotton believed to contain a lower "trash" content than most grades of machine picked cotton. Since the active agent for byssinosis is thought to be contained in the "trash" component of cotton this population should be exposed to dust which is less active in producing acute or chronic respiratory effects. The study group has been exposed to reasonably low dust levels since the introduction of dust controls approximately 20 years ago. This long history of stable exposures along with a reasonable range of exposure will permit the examination of exposure-effect relationships. These can be compared to those published in comparable study populations. (In particular this study design is similar to Merchant's, which provides the basis for the current U.S. standard). Selected for study were two textile mill populations; one exposed to cotton dust (445 cotton mill workers), and the other unexposed (485 silk mill workers). The field survey data were collected during an exchange program between Harvard School of Public Health and Shanghai First Medical College and included demographic data, smoking history, standardized symptomic history (MRC for chronic bronchitis and Schilling for byssinosis), and pulmonary function measurements (forced expiratory efforts on ATS approved equipment) before and after a work shift preceeded by 2 days away from work. Environmental dust sampling was simultaneously conducted, using the Lumsden Vertical Elutriator, in all job groups under study (opening through spinning). Request for support is directed at the analyst of these data 1). to examine the prevalence of byssinosis and chronic bronchitis in the cotton workers with respect to exposures and jobs controlling for confounders and examining interaction with cigarette smoking, 2). to compare the prevalence of chronic bronchitis among cotton textile workers with that for the control group of silk workers, 3). to quantify acute change in lung function and compare this to job and exposure levels controlling for likely confounders and, 4.) to examine cross-sectional lung function in the cotton textile workers for relationship to job or dust exposure adjusting lung function using data from the silk textile workers. The methods of analysis will include multiple logistic and linear regression modeling.